The dot notation works almost everywhere,
but there are some situations
in which we can not use it.
For example, using the dot operator
in the code given below
will result in an error:
This is because
the dot operator needs the key name
to be a proper variable name.
In JavaScript,
you can not have a variable name
that starts with a number.
This is why
our code results in an error.
Now, to access the value of
such properties,
we need a different notation:
the bracket notation.
In the example given below,
we are using the bracket notation,
to read the value stored in the 12 key.
Here's another example where
we are using bracket notation
to read the value stored in
the project-lead key:
In the above example,
we could not have used project.project-lead
because project-lead is not
a proper variable name
because it contains the - character.
We can also use variables inside
the bracket notation.
Look at the example below.
In the example given above,
the key name project-lead
from the project object
is stored inside a variable keyName.